The robotics team at KIPP DC works on Lego robot programming skills in 2011 (Dayna Smith/For The Washington Post)

Jim Horn is the most vocal critic of our nation’s (and the District’s) largest nonprofit charter school network, KIPP. Among journalists, I am KIPP’s most enthusiastic supporter.

That makes me an odd judge of Horn’s new book on KIPP and schools like it, “Work Hard, Be Hard: Journeys Through ‘No Excuses’ Teaching.” But I think he deserves attention as a hard-working scholar and talented writer who brings together, from several sources, concerns about the rapid growth of charter schools similar to KIPP.

I wish the book were not so one-sided. In the great tradition of American polemics, Horn is entitled to his strongly anti-KIPP view. But he never satisfactorily explains how a charter network, if it is as harmful to teachers and children as he says, could attract nearly 70,000 students to 183 campuses in 20 states and the District.

Support for KIPP’s exceptional principal training, teacher creativity and additional learning time is so strong among parents, researchers, politicians, funders, the media and young educators that arguments on the other side often go unheard. Horn examines the thorniest issues, such as the dependence of KIPP-like charters on wealthy foundations and government grants, whose money they use in addition to their per-pupil allotment of tax dollars.

The independently run public charters are usually outside the reach of elected school boards and teacher unions. Some critics say they are out of sync with democratic values and push children too hard. Horn, a professor of educational leadership at Cambridge College in Massachusetts, offers research and personal accounts in his 252-page book, published by Rowman & Littlefield.

The book’s most original contributions are long excerpts from interviews with 23 former KIPP teachers and two former teachers from other schools based on the “no excuses” model of demanding lessons and strong discipline. “I feel like there are a lot of really good teachers who did leave and it wasn’t because they were bad teachers; it was just because they couldn’t deal with the pressure and the hours and the stress that is kind of put upon people,” one interviewee said.

A teacher who got a job in a wealthy community after leaving KIPP said, “I felt like I was almost coming out of, I don’t feel totally right saying this, but I guess I can, in a minor way, understand how military might feel coming home.”

One teacher reported that her KIPP school hid the worst-behaved students in the basement when visitors came by. Such accounts are disturbing if true, but that is difficult to discern. Horn has withheld not only teachers’ names but where and when they taught. He told me one of the former teachers quoted has gone public.

I have criticized KIPP, particularly the early excesses of founders Dave Levin and Mike Feinberg, but Horn’s description of the KIPP environment as “grim and punitive” is as wrong as wrong can be. Horn has yet to visit a KIPP school. I have been in 42 of them, including the basements. Nowhere have I seen children more engaged in their work, more encouraged to speak and write, and happier with the music and games entwined in the teaching.

Horn says the white enthusiasm for KIPP harks back to the Hampton Model of industrial education that “came to embody a systematic method to indoctrinate and pacify the freed black population” after the Civil War. Having been refused access to KIPP Memphis two years ago, he asked me for help. A KIPP spokesman told me the school’s staff had rejected the request because Horn had suggested in one piece that KIPP schools were like concentration camps.

KIPP teachers welcome into their classrooms students who have said worse things about them. KIPP schools have the power to invite Horn if they want to. Why not give it a try? The vibrant creativity of KIPP teachers refutes his dark perspective, and the visit may persuade him to interview at least some of the many people who love those schools.